Polypropylene containing partially hydrolyzed ethylene-vinyl acetate copolymer



United States Patent 3,426,107 POLYPROPYLENE CONTAINING PARTIALLY HYDROLYZED ETHYLENE-VINYL ACETATE COPOLYMER Jack G. Scruggs and Cilton W. Tate, Cary, N.C., assignors to Monsanto Company, St. Louis, Mo., a corporation of Delaware No Drawing. Continuation-in-part of application Ser. No. 187,196, Apr. 13, 1962. This application Nov. 16, 1966, Ser. No. 594,701 US. Cl. 260-897 1 Claim Int. Cl. C08f 29/42, 29/50 ABSTRACT on THE DISCLOSURE This invention relates to compositions of matter comprising polypropylene and partially hydrolyzed copolymers of ethylene and an acyloxy substituted ethylene.

This application is a continuation-in-part of application Ser. No. 187,196, filed on Apr. 13, 1962, now abandoned.

This invention is concerned with shaped articles of polyolefins which have improved dyeability. More particularly, this invention is concerned with a new composition of matter composed of high molecular weight crystalline polypropylene and a copolymer which possessesgreatly increased receptivity for dyestuffs.

Within the last several years, the advent of highly crystalline polyolefins has caused an interest in polypropylene as a fiber forming material. Many articles have appeared in current and past publications advocating the use of polypropylene as a textile fiber. However, it has been pointed out that the success of polypropylene in textile type yarns of from 2 to denier filament would depend to a large extent on the development of efiicient and economic properties, which up to now have been diflicult to build into these tfibers. The present processes of producing these fibers are well known and they produce low priced products; however, a low cost fiber that would require a costly dyeing and finishing method would not be of wide acceptance in the textile industry. It is a well known fact that polypropylene fibers will not be colored by any of the known and conventional dyeing methods. Some polypropylene fibers have been produced in colors, but it appeared that they had been colored by dope dyeing or pigmentation prior to spinning. This was an expensive process and sharply limited the number of colors and shades which were available. It is known in the art to increase the dyeability of these fibers by grafting certain types of polymeric materials onto the fiber itself. This method has the disadvantage of limiting the dyestuffs to only the surface and to a limited depth in the fibers, resulting in susceptibility of the fibers to loss of color by abrasion. Other known methods involve subjecting the polymeric materials to high energy radiation and treatment of the fibers with oxygen or ozone. These methods cause enough degradation of the polymer chain to render them commercially impractical. In addition, chemical treatment of polypropylene by various reagents has given some improvement in dyeability but it was at the expense of spinnability and lowering of the melting point of the polymer.

An object of this invention is to provide a new composition of matter of polyolefins which possesses accept- 3,426,107 Patented Feb. 4, 1969 able dyeing properties. Another object of this invention is to produce a polypropylene which possesses commercially acceptable dyeing properties. Another object of this invention is to provide a method by which polypropylene may be produced which possesses acceptable dyeing properties. Other objects of this invention will hereinafter become apparent in the following detailed description and appended claims.

Generally, the objects of this invention are obtained by blending with polypropylene a partially hydrolyzed copolymer of units of comonomers represented by and CHFCHOY in which R, R R may be hydrogen or alkyl groups or combinations of such and Y may be any acyl groups such as formyl, acetyl or propionyl.

More specifically, polypropylene is blended with a copolymer of the type li.ii... ...l Li. no.

where R, R and [R may be hydrogen, alkyl groups with the alkyl group containing from 1 to 10 carbon atoms, or combinations of same. Y is an acyl group containing from 1 to 10 carbon atoms and It may vary from 10 to 1,000, and has been partially hydrolyzed by any conventional method such as using alcoholic potassium hydroxide. These copolymers include 65 percent ethylene and 35 percent vinyl acetate. lIn addition to the above compounds, the following may be combined or used separately. They are al kylenes such as ethylene, propylene, butene-l, pentene-l and 4-methyl butene. These compounds may be combined with the vinyl acylates such as vinyl formate, vinyl acetate, vinyl propionate, vinyl benzoate and vinyl trichloroacetate. Any combination of these compounds which will give a poly(alkylene-vinyl acylate) may be used in the method of this invention.

The percentage of partially hydrolyzed copolymer to polypropylene may vary from as low as 1 with the preferred being 10 percent of copolymer to percent of polypropylene. Fibers have been spun from percent partially hydrolyzed ethylene-vinyl acetate as well as 100 percent propylene. The partially hydrolyzed copolymer is blended with finely divided polypropylene in any conventional manner such as a V-blendor. The thus blended composition is then melt spun by a conventional melt spinning method. The copolymer should be hydrolyzed to at least 5 percent and less than about 100 percent. It is believed that the conditions for complete hydrolysis of the acylated copolymer tend to effect chain scission and cause color formation. This invention therefore is directed to the use of copolymers which have been partially hydrolyzed. Hydrolysis of the copolymer occurs quite readily to the extent that about 98 percent of the original acyl groups can be converted to hydroxyl groups without adverse affect on the color of the copolymer. Insofar as the economics for further hydrolysis and tendency for coloration mitigate against total hydrolysis the preferred limits of this invention lie in the use of the above defined copolymer which has been hydrolyzed to from about 5 percent to about 98 percent of completion. These blended fibers have shown excellent results 3 with the conventional disperse dyeing method as well as with basic dyeing methods.

The following examples are cited to illustrate the invention. They are not intended to limit it in any way. Unless otherwise noted, percentages as expressed in the examples indicate percent by weight. The components of the dye bath are all based upon the weight of the fiber or sample.

Example 1 A copolymer composed of 65 percent ethylene and percent vinyl acetate (200 grams) was dissolved in 4 liters of toluene by stirring and heating to 85 C. The solution was cooled to about C. A solution of 86.4 grams potassium hydroxide in 3 liters of methanol was prepared and added gradually to the solution of the co polymer in toluene to elfect a partial hydrolysis. This mixture was stirred at 25-35" C. for 3 hours and allowed to stand for 72 hours at 27 C. To this mixture was added a sutficient amount of 0.5 N hydrochloric acid to adjust the pH to about 7. To this neutralized mixture was then added 2 gallons of methanol to precipitate the copolymer which was then removed by filtration. The copolymer was reslurried with 2 liters of water to wash out salts; the slurry was filtered to obtain the copolymer and it was finally dried in a vacuum oven at C. for 12 hours (25 in. vacuum). Comparison of the infrared spectra of a film prepared from this partially hydrolyzed copolymer and a film prepared from the original copolymer showed that hydrolysis was about 50 percent complete.

To 20 grams of this copolymer powdered in a Wiley mill was added 180 grams of powdered polypropylene and this mixture was blended in a V-blendor. This blended mixture was then melt spun by conventional melt spinning techniques and the resulting filaments and fibers were drawn by usual fiber drawing methods. In succeeding examples some of the fibers were not drawn.

A sample of the above undrawn blended fibers of polypropylene, ethylene-vinyl acetate copolymer (hydrolyzed) was subjected to a conventional basic dyeing process. The dye bath was a 40:1 ratio of liquor to fiber and contained 5.0 percent Sevron Blue 2G (C. I. Basic Blue 22) and 12.0 percent urea. The dye bath with fiber sample was heated to 212 F. and maintained at this temperature for 2 hours. There was not enough penetration of the fiber to be commercially acceptable.

Example 2 The exact procedure of Example 1 was repeated in preparing the blended fibers. The fibers were placed in a dye bath of 40:1 ratio of liquor to fiber, the liquor containing 8.0 percent Sevron Blue 2G (C. I. Basic Blue 22), 2 grams/liter chlorobenzene, 1 gram/liter of Duponol ME (sodium lauryl sulfate) and 0.5 gram/liter of cetyl alcohol. The bath with the fibers immersed was then heated to 212 F. and maintained at that temperature for 2 hours. The fibers were then withdrawn, rinsed in cool water, given a neutral scour and dried. The fibers were then checked by microscopic examination of a crossseetion sample and it was found there was dye penetration to the center of the fibers but it was present in concentric rings of varying concentration.

Example 3 The exact procedure of Example 1 was used in preparing the blended fibers. The fibers were placed in a dye bath of 40:1 ratio of liquor to fiber, the liquor containing 2.0 percent Cibacete Brilliant Blue BG New (C. I. Disperse Blue 3), 1 gram/liter of sodium dibasic phosphate, 1 gram/liter of sodium monobasic phosphate, and 1.0 percent of Igepon T-33 (sodium N-methyl-N-oleoyl taurate). The bath with the fibers was heated to 212 F. and maintained at that temperature for 2 hours. The fibers were then withdrawn, rinsed in cool water, given a neutral scour and dried. The fibers were then checked as in Example 2 and there was complete and uniform penetration of the fibers by the dye.

Example 4 The exact procedure of Example 1 was used in preparing the blended fibers. The fibers were placed in a dye bath, of 40:1 ratio of dye bath liquor to fiber, the liquor containing 2 grams/liter of chlorobenzene, 8.0 percent Sevron Blue 2G (C. I. Basic Blue 22), 1 gram/ liter of Duponol ME, defined fully hereinbefore, and 0.5 gram/liter of cetyl alcohol. The bath with the fibers immersed was heated to 212 F. and maintained at this temperature for 2 hours. The fibers were then checked as before and it was found that some of them were fully penetrated and some were not fully penetrated by the dye.

Example 5 The exact procedure of Example 4 was used in preparing the blended fibers. The fibers were placed in a dye bath of 40:1 ratio of dye bath liquor to fiber, the liquor containing 2.0 percent Cibacete Brilliant Blue BG New (C. I. Disperse Blue 3), 1 gram/liter of sodium dibasic phosphate, 1 gram/liter of sodium monobasic phosphate and 1.0 percent of Igepon T-33, fully described hereinbefore. The bath with the fibers immersed was heated to 212 F. and maintained at that temperature for 2 hours. The fibers were then removed, rinsed in cool water, given a neutral scour and dried. The fibers were then checked as above and it was found that there was complete and full penetration of the fibers by the dye.

Example 6 The exact procedure of Example 4 was used in preparing the blended fibers. The fibers were placed in a dye bath of 40:1 ratio of dye bath liquor to fiber, the liquor containing 2 grams/liter of Calro-Victoria Blue Base (C. I. Solvent Blue 4), 2 grams/liter of chloro-benzene, 1 gram/liter of Duponol ME, fully defined hereinbefore, and 0.5 gram/liter of cetyl alcohol. The bath with the fibers immersed was heated to 212 F and maintained at that temperature for 2 hours. The fibers were then removed, rinsed in cool water, given a neutral scour and dried. The fibers were then checked as above and it was found that there was complete and full penetration of the fibers by the dye.

Example 7 The exact procedure of Example 1 was used in preparing the blended fibers except the fibers were drawn and treated with a 10% solution of succinic anhydride in toluene. The fibers were placed in a dye bath of 40:1 ratio of dye bath liquor to fiber, the liquor containing 8.0 percent Sevron Blue 2G (C.I. Basic Blue 22), 2 grams/liter of chlorobenzene, 1 gram/liter of Duponol ME, fully defined hereinbefore, and 0.5 gram/liter of cetyl alcohol. The bath with the fibers immersed was heated to a temperature of 212 F. and maintained at that temperature for 2 hours. The fibers were then removed, rinsed in cool water, given a neutral scour and dried. The fibers were then checked as above and it was found that there was complete and uniform penetration of the fibers by the dye.

Thus, with some slight variations, in the methods of dyeing it was possible to satisfactorily dye the blended fibers of this invention. There was complete and uniform penetration of the fibers by the dyes and their colors or hues were completely acceptable.

It is understood that changes and variations may be made in the present invention by one skilled in the art without departing from the spirit and scope thereof as defined in the appended claim.

We claim:

1. Crystalline polypropylene having blended therewith in an amount sutficient to enhance the dyeability of said polypropylene a partially hydrolyzed copolymer of about 65 percent by weight of ethylene and about 35 percent 6 by Weight of vinyl acetate, said copolymer having been 3,248,359 4/1966 Maloney 260-897 XR hydrolyzed to a degree ranging from 5 percent to 98 per- 3,303,148 2/1967 Joyner et a1 260-897 XR cent of completion.

GEORGE F. LESMES, Primary Examiner. References Cited UNITED STATES PATENTS -R- 3,226,455 12/1965 Matsubayashi et a1. 260-897 8-55; 260-873, 80.75 

